Video terminal, video terminal communicating system, and videoconference system

ABSTRACT

The screen layout of a main screen and a subscreen is optimized, depending on the types of images to be displayed on the main screen and the subscreen. A video terminal, capable of displaying a subscreen within a main screen, is equipped with a signal control unit 15 as means for optimizing the main screen/subscreen layout, depending on the types of images to be displayed on the main screen and the subscreen. When the main screen is in a split composite screen mode, the signal control unit 15 allows a subscreen to be displayed on a screen of a television 11, with the subscreen occupying one section of the split composite screen. When the main screen is in a full screen mode, the signal control unit 15 allows a subscreen to be diminished.

FIELD OF THE INVENTION

[0001] The present invention relates to a video terminal such as avideophone terminal and a video conferencing terminal. In more detail,the invention relates to a video terminal which is capable of displayinga subscreen within a main screen, and a video terminal communicationsystem and a video conferencing system using such video terminals.

BACKGROUND ART

[0002] Conventionally, there has been a video terminal which is capableof displaying a subscreen (e.g. a {fraction (1/9)}-size subscreen)within a main screen, with the subscreen being arranged to displayanimations. In this conventional video terminal, users can select whatto display on the main screen and the subscreen and where to place thesubscreen on the display (specifically, wherever of four areas: topleft, bottom left, top right, and bottom right) at their will.

[0003] However, no existing system permits automatic selection andswitchover of screen layouts of the main screen and the subscreen.

[0004] With respect to the video conferencing system, one type of systemhas been recently gaining popularity, namely, a system which utilizes amultipoint control unit for connecting multiple video terminals viacommunication lines. The multipoint control unit (MCU) used in thisvideo conferencing system has a continuous presence function. Wherevideo terminals at four locations are connected together, the screen ofeach terminal is divided into four sections and displays images from allterminals.

[0005] While this video terminal displays a four-split composite screen,each section may further contain a subscreen, for example, in {fraction(1/9)} scale. In this situation, however, the screen layout is socomplicated as to spoil the total balance. Besides, when each section ofthe four-split composite screen includes a {fraction (1/9)}-sizesubscreen, the view of each section itself is seriously impaired.Further, as far as this four-split composite screen is concerned, one ofthe four sections contains a subscreen of the identical image (providedthat the image is an animation). This is an inefficient screen layout.

[0006] The present invention is made in order to solve these problems.An object of the invention is to provide a video terminal, a videoterminal communication system, and a video conferencing system, whereinthe screen layout of the main screen and the subscreen is automaticallychanged and optimized through selection of the types of images to bedisplayed on the main screen and the subscreen.

SUMMARY OF THE INVENTION

[0007] In order to solve the above problems, the invention concerns avideo terminal which is capable of displaying a subscreen within a mainscreen. This video terminal is characterized in comprising means foroptimizing a screen layout of the main screen and the subscreen,depending on the types of images to be displayed on the main screen andthe subscreen.

[0008] With respect to the above arrangement, the video terminal of theinvention is characterized in that when the subscreen displays a stillimage, the optimizing means allows the subscreen to be enlarged. Alsowith respect to the above arrangement, the video terminal of theinvention is characterized in that when the main screen is in a splitcomposite screen mode, the optimizing means allows the subscreen tooccupy one section of the split composite screen. Besides, when the mainscreen is in a full screen mode, the optimizing means allows thesubscreen to be diminished.

[0009] The invention also concerns a video conferencing system which ischaracterized in comprising multiple video terminals of the abovearrangements, and a multipoint control unit which connects these videoterminals together via communication lines. This video conferencingsystem is also characterized in that each of the video terminals selectsthe type of image to be displayed on the main screen, and that themultipoint control unit determines a display position of the subscreen,depending on the selected type of image to be displayed on the mainscreen.

[0010] The invention further concerns a video terminal communicationsystem which is characterized in comprising video terminals of each ofthe above arrangements, with a point-to-point connection beingestablished between the video terminals via a communication line. Thisvideo terminal communication system is also characterized in that eachof the video terminals comprises: transmission means for transmitting adisplay mode specification command to the other video terminal via thecommunication line, with a screen layout of the main screen and thesubscreen being optimized by the optimizing means and specified by thedisplay mode specification command; receiving means for receiving adisplay mode specification command which is transmitted from the othervideo terminal via the communication line; and switching means forswitching screen layouts in accordance with the display modespecification command which is received by the receiving means.

[0011] The invention again concerns a video conferencing system which ischaracterized in comprising multiple video terminals of the abovearrangements, and a multipoint control unit which connects these videoterminals together via communication lines. This video conferencingsystem is also characterized in that each of the video terminalscomprises: transmission means for transmitting display modespecification commands to the multipoint control unit via one of thecommunication lines, with a screen layout of the main screen and thesubscreen being optimized by the optimizing means and specified by thedisplay mode specification commands; receiving means for receiving adisplay mode specification command which is transmitted from themultipoint control unit via the one communication line; and switchingmeans for switching screen layouts in accordance with the display modespecification command which is received by the receiving means. Thisvideo conferencing system is further characterized in that themultipoint control unit comprises relay means for receiving the displaymode specification commands from each video terminal and transmittingthem to the other video terminals.

[0012] The video terminal of the invention, capable of displaying asubscreen within a main screen, is arranged to comprise means foroptimizing a screen layout of the main screen and the subscreen,depending on the types of images to be displayed on the main screen andthe subscreen. As a result, it is possible to display the main screenand the subscreen in an optimum screen layout, simply by selecting thetypes of main screen and subscreen.

[0013] When the subscreen displays a still image, the video terminal ofthe invention is arranged to enlarge the subscreen. Accordingly, a stillimage such as text information can be always displayed on the screen ina clear view.

[0014] The video terminal of the invention is arranged to allow thesubscreen to occupy one section of the split composite screen. Besides,when the main screen is in a full screen mode, the video terminal isarranged to diminish the subscreen. Therefore, the subscreen can bealways displayed in an optimum screen layout, depending on the type ofmain screen.

[0015] The video conferencing system of the invention comprises multiplevideo terminals and a multipoint control unit which connects these videoterminals together via communication lines. Each of the video terminalsis arranged to select the type of image to be displayed on the mainscreen, and the multipoint control unit is arranged to determine adisplay position of the subscreen, depending on the type of main screenimage. As a result, the subscreen can be always displayed at an optimumposition relative to the main screen.

[0016] The video terminal communication system of the inventioncomprises video terminals which establish a point-to-point connectionvia a communication line. Each of the video terminals is arranged tocomprise: transmission means for transmitting a display modespecification command to the other video terminal via the communicationline, with a screen layout of the main screen and the subscreen beingoptimized by the optimizing means and specified by the display modespecification command; receiving means for receiving a display modespecification command which is transmitted from the other video terminalvia the communication line; and switching means for switching screenlayouts in accordance with the display mode specification command whichis received by the receiving means. Therefore, if the user of a terminalwishes to send data or the like to the user of the other terminal, thedata can be displayed at the other terminal in an optimum screen layout,without any manipulation by the user of the other terminal.

[0017] Again, the video conferencing system of the invention comprisesmultiple video terminals, and a multipoint control unit which connectsthese video terminals together via communication lines. Each of thevideo terminals is arranged to comprise: transmission means fortransmitting display mode specification commands to the multipointcontrol unit via one of the communication lines, with a screen layout ofthe main screen and the subscreen being optimized by the optimizingmeans and specified by the display mode specification commands;receiving means for receiving a display mode specification command whichis transmitted from the multipoint control unit via the onecommunication line; and switching means for switching screen layouts inaccordance with the display mode specification command which is receivedby the receiving means. The multipoint control unit is arranged tocomprise relay means for receiving the display mode specificationcommands from each video terminal and transmitting them to the othervideo terminals. Therefore, if the user of a terminal wishes to senddata or the like for a meeting to the users of the other terminals, thedata for a meeting can be displayed at the other terminals in an optimumscreen layout, without any manipulation by the users of the otherterminals.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 is an explanatory view showing the overall configuration ofa video conferencing system which employs video terminals of theinvention.

[0019]FIG. 2 is a more specific block diagram showing the configurationof a video conferencing terminal.

[0020]FIG. 3 is a flowchart which illustrates display mode switchoveroperations at each video conferencing terminal employed in a videoconferencing system.

[0021]FIG. 4 is a flowchart which illustrates display mode switchoveroperations at each video conferencing terminal employed in a videoconferencing system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Embodiments of the invention are hereinafter described withreference to the drawings.

[0023]FIG. 1 is an explanatory view showing the overall configuration ofa video conferencing system which employs video terminals of theinvention.

[0024] This video conferencing system comprises multiple video terminals(hereinafter called “video conferencing terminals”) 1 a, 1 b . . . 1 n,and a multipoint control unit (MCU) 3 which connects the multiple videoconferencing terminals 1 a, 1 b . . . 1 n via communication lines 2 a, 2b . . . 2 n.

[0025] As shown in FIG. 2, each of the video conferencing terminals 1 a,1 b . . . 1 n is constituted with a television 11 which is used as apicture information display unit and an audio information output unit, atelevision camera 12 as a picture information acquisition unit, amicrophone 13 as an audio information acquisition unit, a keyboard 14 asa text information input unit, and a signal control unit 15 such as amultiplexer. The signal control unit 15 is interposed between andconnected to these components and their corresponding communicationlines 2 a, 2 b . . . . . 2 n, and controls input and output of signalsacross those components and their communication lines 2 a, 2 b . . . 2n. To give another example, the video conferencing terminals 1 a, 1 b .. . 1 n may be personal computers each of which is composed of a displayunit, a speaker, a camera, a microphone, a keyboard and an internalmodem.

[0026] The communication line may be an ISDN (Integrated Serva Network)line or a high-speed digital leased line, to name a few.

[0027] In the video conferencing system of this arrangement, each of thevideo conferencing terminals 1 a, 1 b . . . 1 n can simultaneouslydisplay images from four locations including the own terminal, with ascreen of the television 11 (hereinafter called “television screen”)being split into four sections. In addition, the present embodimentsenable a {fraction (1/9)}-size subscreen to appear within a main screen(a full screen or the whole of the four-split composite screen).

[0028] The keyboard 14 is equipped with a selection key (not shown) forselecting the types of images to be displayed on the main screen and thesubscreen. Also provided is switching means which automatically switchesthe screen layouts (display size and display position) of the mainscreen and the subscreen, based on the manipulation of the selectionkey. As the switching means, the present embodiments adopt the signalcontrol unit 15. In the case of a personal computer, the switching meansis realized by a system controller which controls the entire computeroperations. Further, the switching means executes an operation accordingto a display mode switchover process program which is stored in aninternal ROM (not shown). Incidentally, the display modes for the mainscreen include a full screen view (where a single section occupies theentire screen) and a four-split view. The types of main screen includean incoming animation and a still image, whereas the types of subscreeninclude an incoming animation, an outgoing animation and a still image.

[0029] With regard to the video conferencing system of the abovearrangement, each of the video conferencing terminals 1 a, 1 b. . . 1 nperforms display mode switchover operations, as detailed below withreference to the flowcharts in FIG. 3 and FIG. 4. The flowchart in FIG.3 concerns the case where the main screen is in a four-split compositescreen mode, whereas the flowchart in FIG. 4 concerns the case where themain screen is in a full screen mode.

[0030] As mentioned already, the display modes for the main screeninclude a full screen view (where a single section occupies the entirescreen) and a four-split view. The types of main screen include anincoming animation and a still image, whereas the types of subscreeninclude an incoming animation, an outgoing animation and a still image.

[0031] Under such circumstances in the present embodiments, thecombination of the main screen and the subscreen (main screen/subscreen)is selectable from three types: (1) Incoming animation/Outgoinganimation, (2) Still image/Incoming animation, and (3) Incominganimation/Still image. In addition, the full screen mode and thefour-split composite screen mode are available for an incoming animationor animations. To be specific, the MCU 3 adopts the full screen mode andthe four-split composite screen mode, while the point-to-pointconnection between the video conferencing terminals 1 a, 1 b . . . 1 nadopts the full screen mode.

[0032] [1] When the main screen is in the four-split composite screenmode

[0033] In this case, the selection key is manipulated (S1) to showincoming animations on the main screen in the four-split compositescreen mode and to show an outgoing animation on the subscreen (S2).Based on this selected combination, the display mode switching meansallows an outgoing animation to be displayed on a ¼-size subscreen, at asection allotted to the own terminal (S3 to S4). At this stage, if thedisplay is off in the section for the own terminal (Yes in S3) and alsoif the four-split composite screen has a blank section (Yes in S5), theoutgoing animation is shown on a ¼-size subscreen at the blank section(S6). If there is no blank section (No in S5), the outgoing animation isforced to appear on a ¼-size subscreen, at the bottom right part of thescreen (S7). In addition, if the locational information is unavailable,the outgoing animation is forced to appear on a ¼-size subscreen, at thebottom right part of the screen.

[0034] In another case, suppose that the selection key is manipulated(S1) to show still images on the main screen and to select an incominganimation on the subscreen (S2). Based on this selected combination, thedisplay mode switching means forces an incoming animation to appear on a¼-size subscreen, at the bottom right part of the screen (S8).

[0035] In yet another case, suppose that the selection key ismanipulated (S1) to show incoming animations on the main screen in thefour-split composite screen mode and to show a still image on thesubscreen (S2). Based on this selected combination, the display modeswitching means allows a still image to be displayed on a ¼-sizesubscreen, at a section allotted to the own terminal (S9 to S10). Atthis stage, if the display is off in the section for the own terminal(Yes in S9) and also if the four-split composite screen has a blanksection (Yes in S11), the still image is shown on a ¼-size subscreen atthe blank section (S12). If there is no blank section (No in S11), thestill image is forced to appear on a ¼-size subscreen, at the bottomright part of the screen (S13). In addition, if the locationalinformation is unavailable, the still image is forced to appear on a¼-size subscreen, at the bottom right part of the screen.

[0036] [2] When the main screen is in the full screen mode

[0037] In this case, the selection key is manipulated (S21) to show anincoming animation on the main screen in the full screen mode and toshow an outgoing animation on the subscreen (S22). Based on thisselected combination, the display mode switching means allows anoutgoing animation to appear on a {fraction (1/9)}-size subscreen, atthe bottom right part of the screen (S23).

[0038] In another case, suppose that the selection key is manipulated(S21) to show a still image on the main screen in the full screen modeand to show an incoming animation on the subscreen (S22). Based on thisselected combination, the display mode switching means allows anincoming animation to appear on a {fraction (1/9)}-size subscreen, atthe bottom right part of the screen (S24).

[0039] In yet another case, suppose that the selection key ismanipulated (S21) to show an incoming animation on the main screen inthe full screen mode and to show a still image on the subscreen (S22).Based on this selected combination, the display mode switching meansallows a still image to appear on a ¼-size subscreen, at the bottomright part of the screen (S25).

[0040] Concerning the above embodiments, the size of the subscreen isselected from ¼ or {fraction (1/9)}. However, these sizes are merelygiven for the purpose of description and should not be construed tolimit the subscreen size. Besides, the initial display position of thesubscreen should not be limited to the bottom right part of the display.Further, the main screen may be split into any number of sections,instead of four. To put it simply, the greatest feature of the inventionis to automatically optimize the screen layouts in the following manner.First, when the subscreen shows a still image, the subscreen is enlargedin size (¼-size in the above-described operations) as compared withconventional subscreens, in order to ensure a clear view of thesubscreen. Second, when the main screen is in the full screen mode, thesubscreen is diminished in size ({fraction (1/9)}-size in theabove-described operations) so as not to obstruct the main screen.

[0041] Regarding the display mode switching process by the switchingmeans, the display size and display position as mentioned above shouldbe understood to refer to the initial size and position in response tothe manipulation of the selection key. Later, a user can change thedisplay size and display position at his/her will by manipulating thekeyboard 14 or the like, as in the conventional cases.

[0042] As far as the above-described operations are concerned, theselections are effected at the own terminal alone. However, consideringthe use of the video conferencing terminals 1 a, 1 b . . . 1 n in thevideo conferencing system, it is convenient if the main screen/subscreencombination can be selected at the own terminal and then can beautomatically set to the other terminals connected by the MCU 13. Fromthis point of view, the present invention is arranged to transmitdisplay mode specification commands which specify a mainscreen/subscreen combination selected at the own terminal, from the ownterminal to the other terminals via their communication lines 2 a, 2 b .. . 2 n and the MCU 13. On receiving the display mode specificationcommands, the other terminals execute the above operations (theoperations shown in FIG. 3 and FIG. 4), according to the mainscreen/subscreen combination specified by the display mode specificationcommands. Eventually, each of the other terminals selectively displaysthe main screen and the subscreen, just as the selection is made by thekeyboards 14 of its own terminal. In order to enable transmission andreceipt of the display mode specification commands across the terminals,the MCU 13 additionally needs to have relay means for relaying thedisplay mode specification commands. This arrangement corresponds toclaim 6. Moreover, where any two video conferencing terminals establisha point-to-point connection via a communication line withoutinterposition of the MCU 13, a display mode specification command can besent and received as well. This arrangement corresponds to claim 5.

INDUSTRIAL APPLICABILITY

[0043] As described above, the video terminal, the video terminalcommunication system and the video conferencing system concerning thepresent invention are suitable for use in a video conference.

1. A video terminal capable of displaying a subscreen within a mainscreen, characterized in comprising means for optimizing a screen layoutof the main screen and the subscreen, depending on the types of imagesto be displayed on the main screen and the subscreen.
 2. A videoterminal according to claim 1, characterized in that when the subscreendisplays a still image, the optimizing means allows the subscreen to beenlarged.
 3. A video terminal according to claim 1, characterized in:that when the main screen is in a split composite screen mode, theoptimizing means allows the subscreen to occupy one section of the splitcomposite screen; and that when the main screen is in a full screenmode, the optimizing means allows the subscreen to be diminished.
 4. Avideo conferencing system characterized in comprising multiple videoterminals according to any of claims 1 to 3, and a multipoint controlunit which connects these video terminals together via communicationlines, and also characterized in: that each of the video terminalsselects the type of image to be displayed on the main screen; and thatthe multipoint control unit determines a display position of thesubscreen, depending on the selected type of image to be displayed onthe main screen.
 5. A video terminal communication system characterizedin comprising video terminals according to any of claims 1 to 3, with apoint-to-point connection being established between the video terminalsvia a communication line, and also characterized in that each of thevideo terminals comprises: transmission means for transmitting a displaymode specification command to the other video terminal via thecommunication line, with a screen layout of the main screen and thesubscreen being optimized by the optimizing means and specified by thedisplay mode specification command; receiving means for receiving adisplay mode specification command which is transmitted from the othervideo terminal via the communication line; and switching means forswitching screen layouts in accordance with the display modespecification command received by the receiving means.
 6. A videoconferencing system characterized in comprising multiple video terminalsaccording to any of claims 1 to 3, and a multipoint control unit whichconnects these video terminals together via communication lines, andalso characterized in that each of the video terminals comprises:transmission means for transmitting display mode specification commandsto the multipoint control unit via one of the communication lines, witha screen layout of the main screen and the subscreen being optimized bythe optimizing means and specified by the display mode specificationcommands; receiving means for receiving a display mode specificationcommand which is transmitted from the multipoint control unit via theone communication line; and switching means for switching screen layoutsin accordance with the display mode specification command which isreceived by the receiving means; and that the multipoint control unitcomprises relay means for receiving the display mode specificationcommands from each video terminal and transmitting them to the othervideo terminals.